×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Ground Potential Rise Transfer

Ground Potential Rise Transfer

Ground Potential Rise Transfer

(OP)
I am looking at an surface mining installation which has a 66/22kV substation suppling a large mobile electrical load (5-10MVA) via a 22kV above ground cable (max 2.5 miles long).  The cable earth is connected to the 22kV neutral at the substation.  The mobile load has operators and there is no earthing grid associated with it.

The concern is that a 66kV fault will cause a Ground Potential Rise (GPR) at the substation which will be transfered via the 22kV cable earth to the mobile load resulting in step and touch voltage issues at the load. Worst case being a 66kV fault at the substation itself.

Limiting the 66kV earth fault is expensive (requires the installation of a >30MVA 1:1 Delta Wye isolating transformer with a NER).  The effectiveness of reducing the earthing resistance at the substation (using copper in the ground and parallel paths connected via the 66kV line overhead earth is also limited).

Does anyone have a suggestion for another suitable means of reducing the possible step and touch voltages at the mobile plant arising from earth faults on the 66kV side?      

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources